A published report says the United States is aware that a new generation of al-Qaida leadership under Osama bin Laden is emerging in Pakistan's tribal areas.

The New York Times reports Monday that U.S. intelligence officials say the new leaders rose within the group's ranks following the death or capture of operatives following the September 11, 2001 terrorist attacks in the United States.

But authorities are quoted as saying they know little of how the new leadership in Pakistan communicates with bin Laden. The officials also say the new al-Qaida hierarchy is not reliant on constant contact with the terrorist group's leader.

Officials told the newspaper that new information has led the U.S. intelligence community to reassess al-Qaida's strength, and to realize its leadership has not been as badly crippled by counter-terrorism efforts as previously thought.

Officials and analysts describe the new generation of terrorist leaders as being in their mid-30s, battle-hardened, and more diverse in their origins than previous al-Qaida leaders.

The Times reports that experts say even though the group al-Qaida in Iraq is largely separate from the main al-Qaida organization in Pakistan, the fighting in Iraq will likely produce the terrorist network's future leaders.

Officials say U.S., European and Pakistani authorities are learning about the new terrorist leaders from investigations, and from interrogations of terrorist suspects.